Optical communication system and optical line terminating apparatus

Abstract

There is provided an abnormal light cut-off system in which even when a high power light is inputted from an optical fiber connected to a user side apparatus by a malicious user or an accident, a trouble rate is low, the abnormal light is cut off at high sensitivity, and security is high. In a network system in which an optical line terminating apparatus and plural optical network apparatuses are connected together via plural optical connection sections and an optical branching section, the optical branching section includes one optical line terminating apparatus side port and plural optical network apparatus side branch ports, an optical line terminating apparatus side optical fiber connects the optical line terminating apparatus and the one optical line terminating apparatus side port, an optical branching section side optical fiber connects the optical network apparatus side branch port and a light cut-off section, and an optical network apparatus side optical fiber connects the light cut-off section and the optical network apparatus. When an abnormal light is inputted from the optical network apparatus side, it is cut off by the light cut-off section.

1. An optical communication system in which an optical line terminating apparatus and a plurality of optical network apparatuses are connected together via an optical line terminating apparatus side optical fiber connected to the optical line terminating apparatus, a plurality of optical fibers respectively connected to the plurality of optical network apparatuses, and an optical branching section to connect the optical line terminating apparatus side optical fiber and the plurality of optical fibers, wherein
 the optical line terminating apparatus includes a wavelength division multiplexing section, a first optical coupler, a light receiving section, a light transmitting section, a first light reception section, a first detection section, and a first control section, 
 the optical branching section includes one optical line terminating apparatus side port, a plurality of optical network apparatus side branch ports, a plurality of light cut-off sections, an optical splitter, a second optical coupler, a second light reception section, a second detection section, and a second control section, 
 in the optical line terminating apparatus, the first optical coupler branches a signal from the wavelength division multiplexing section to the first light reception section and the light receiving section and outputs it, the first light reception section converts the optical signal into an electrical signal and outputs it to the first detection section, and when an abnormal signal light is inputted, the first detection section uses a dynamic bandwidth assignment function to detect that the signal from which optical network apparatus is abnormal, the first control section forms, based on the detection result, light cut-off control information indicating that the signal from which optical network apparatus is to be cut off, and outputs the light cut-off control information by the transmitting section through the wavelength division multiplexing section, 
 the optical branching section receives the light cut-off control information through the optical line terminating apparatus side optical fiber, the second optical coupler branches the signal from the optical line terminating apparatus to the optical splitter and the second light reception section and outputs it, the second light reception section converts the optical signal into an electrical signal and outputs it to the second detection section, the second detection section detects the light cut-off control information, the second control section controls the light cut-off section corresponding to the optical network apparatus side optical fiber connected to the optical network apparatus indicated by the light cut-off control information, and the light cut-off section cuts off the optical signal sent from the optical network apparatus. 
 
     
     
       2. The optical communication system according to  claim 1 , wherein the abnormal signal light is a high power light of a previously set value or higher. 
     
     
       3. The optical communication system according to  claim 1 , wherein based on a timing assigned to the optical network apparatus by the optical line terminating apparatus, the first detection section of the optical line terminating apparatus determines that the input light is the signal inputted from which optical network apparatus, and detects that the signal from which optical network apparatus is abnormal. 
     
     
       4. The optical communication system according to  claim 1 , wherein the first control section uses an operation and maintenance (OAM) function to send the cut-off control information. 
     
     
       5. An optical line terminating apparatus in an optical communication system in which the optical line terminating apparatus and a plurality of optical network apparatuses are connected together via an optical line terminating apparatus side optical fiber connected to the optical line terminating apparatus, a plurality of optical connection sections respectively connected to the plurality of optical network apparatuses, and an optical branching section to connect the optical line terminating apparatus side optical fiber and the plurality of optical connection sections,
 the optical line terminating apparatus comprising a wavelength division multiplexing section, a first optical coupler, a light receiving section, a light transmitting section, a first light reception section, a first detection section, and a first control section, wherein the first optical coupler branches a signal from the wavelength division multiplexing section to the first light reception section and the light receiving section and outputs it, the first light reception section converts the optical signal into an electrical signal and outputs it to the first detection section, and when an abnormal signal light is inputted, the first detection section uses a dynamic bandwidth assignment function to detect that the signal from which optical network apparatus is abnormal, the first control section forms, based on the detection result, light cut-off control information indicating that the signal from which optical network apparatus is to be cut off, and outputs the light cut-off control information by the transmitting section through the wavelength division multiplexing section, and 
 in the optical branching section, the optical signal from the optical network apparatus indicated by the light cut-off control information is cut off. 
 
     
     
       6. The optical line terminating apparatus according to  claim 5 , wherein the abnormal signal light is a high power light of a previously set value or higher. 
     
     
       7. The optical line terminating apparatus according to  claim 5 , wherein based on a timing assigned to the optical network apparatus by the optical line terminating apparatus, the first detection section determines that the input light is the signal inputted from which optical network apparatus, and detects that the signal from which optical network apparatus is abnormal. 
     
     
       8. The optical line terminating apparatus according to  claim 5 , wherein the first control section uses an operation and maintenance (OAM) function to send the cut-off control information. 
     
     
       9. An optical communication system in which an optical line terminating apparatus and a plurality of optical network apparatuses are connected together via a plurality of optical connection sections and an optical branching section, wherein
 the optical connection sections include an optical line terminating apparatus side optical fiber, a plurality of optical branching section side optical fibers, a plurality of light cut-off sections, and a plurality of optical network apparatus side optical fibers, 
 the optical branching section includes one optical line terminating apparatus side port and a plurality of optical network apparatus side branch ports, 
 the optical line terminating apparatus side optical fiber connects the optical line terminating apparatus and the one optical line terminating apparatus side port, 
 the optical branching section side optical fiber connects the optical network apparatus side branch port and the light cut-off section, 
 the optical network apparatus side optical fiber connects the light cut-off section and the optical network apparatus, and 
 when an abnormal signal light is inputted from the network apparatus side to the light cut-off section, the light cut-off section cuts off the abnormal signal light; wherein a length of the optical branching section side optical fiber is shorter than a length of the optical network apparatus side optical fiber, 
 wherein the light cut-off section includes an optical fuse which is cut by a high power light, and 
 in the optical fuse, an optical power by which optical cut-off is caused is not higher than a value obtained by adding a loss of the optical line terminating apparatus side optical fiber, a loss of the optical branching section, and a loss of the optical branching section side optical fiber to a permissible optical power of the optical line terminating apparatus. 
 
     
     
       10. An optical communication system in which an optical line terminating apparatus and a plurality of optical network apparatuses are connected together via a plurality of optical connection sections and an optical branching section, wherein
 the optical connection sections include an optical line terminating apparatus side optical fiber, a plurality of optical branching section side optical fibers, a plurality of light cut-off sections, and a plurality of optical network apparatus side optical fibers, 
 the optical branching section includes a plurality of light cut-off sections, an optical splitter, an optical coupler, a light reception section, a detection section, and a control section, 
 the optical line terminating apparatus side optical fiber connects the optical line terminating apparatus and the optical coupler, 
 the optical branching section side optical fiber connects the optical splitter and the light cut-off section, 
 the optical network apparatus side optical fiber connects the light cut-off section and the optical network apparatus, 
 the optical coupler branches signals from the plurality of optical network apparatuses to the optical line terminating apparatus side optical fiber and the light reception section and outputs them, and the light reception section converts an optical signal into an electrical signal and outputs it to the detection section, and 
 when an abnormal signal light is inputted from the network apparatus side to the light reception section, based on information detected by the detection section, the control section controls to cut off the optical signal by one of or all of the light cut-off sections, 
 wherein in the control section, when an optical cut-off optical power is not higher than a value obtained by adding a loss of the optical line terminating apparatus side optical fiber, a loss of the optical branching section, and a loss of the optical branching section side optical fiber to a permissible optical power of the optical line terminating apparatus, the light cut-off section cuts off the optical signal. 
 
     
     
       11. An optical communication system in which an optical line terminating apparatus and a plurality of optical network apparatuses are connected together via a plurality of optical connection sections and an optical branching section, wherein
 the optical connection sections include an optical line terminating apparatus side optical fiber, a plurality of optical branching section side optical fibers, a plurality of light cut-off sections, and a plurality of optical network apparatus side optical fibers, 
 the optical branching section includes a plurality of light cut-off sections, an optical splitter, an optical coupler, a light reception section, a detection section, and a control section, 
 the optical line terminating apparatus side optical fiber connects the optical line terminating apparatus and the optical coupler, 
 the optical branching section side optical fiber connects the optical splitter and the light cut-off section, 
 the optical network apparatus side optical fiber connects the light cut-off section and the optical network apparatus, 
 the optical coupler branches signals from the plurality of optical network apparatuses to the optical line terminating apparatus side optical fiber and the light reception section and outputs them, and the light reception section converts an optical signal into an electrical signal and outputs it to the detection section, and 
 when an abnormal signal light is inputted from the network apparatus side to the light reception section, based on information detected by the detection section, the control section controls to cut off the optical signal by one of or all of the light cut-off sections, wherein the detection section has a function to analyze monitor control information of a PON frame of an optical signal, and when an unauthorized signal is detected, the control section controls the relevant light cut-off section to cut off the optical signal.